← Back to Physics-I

Work Power and Energy

267 Questions Start Errorless Test
All Exams Allen Objective Errorless
AFMC 1999; Pb. PMT 2003 Q226 Errorless 1. Work Done by Constant Force MCQ
The work done in pulling up a block of wood weighing 2 kN for a length of 10m on a smooth plane inclined at an angle of $15^{\circ}$ with the horizontal is $[\sin15^{\circ}=0.2588]$
A.
4.36 kJ
B.
5.17 kJ
C.
8.91 kJ
D.
9.82 kJ
RPMT 1999; DCE 2003 Q227 Errorless 5. Elastic and Inelastic Collision MCQ
A space craft of mass 'M' and moving with velocity 'v' suddenly breaks in two pieces of same mass m. After the explosion one of the mass 'm' becomes stationary. What is the velocity of the other part of craft
A.
$\frac{Mv}{M-m}$
B.
v
C.
$\frac{Mv}{m}$
D.
$\frac{M-m}{m}v$
IIT-JEE 1999; UPSEAT 2003 Q228 Errorless 7. Critical Thinking MCQ
A particle free to move along the x-axis has potential energy given by $U(x)=k\left[1-\exp\left(-x\right)^{2}\right]$ for $-\infty\leq x\leq+\infty$ , where k is a positive constant of appropriate dimensions. Then
A.
At point away from the origin, the particle is in unstable equilibrium
B.
For any finite non-zero value of $x$ , there is a force directed away from the origin
C.
If its total mechanical energy is $k/2$ , it has its minimum kinetic energy at the origin
D.
For small displacements from x=0, the motion is simple harmonic
RPET 1999, 2001; UPSEAT 2002 Q229 Errorless 7. Critical Thinking MCQ
A shell is fired from a cannon with velocity v m/sec at an angle $\theta$ with the horizontal direction. At the highest point in its path it explodes into two pieces of equal mass. One of the pieces retraces its path to the cannon and the speed in m/sec of the other piece immediately after the explosion is
A.
$3v \cos \theta$
B.
$2v \cos \theta$
C.
$\frac{3}{2}v \cos \theta$
D.
$\frac{\sqrt{3}}{2}v \cos \theta$
CBSE PMT 1998; Kerala PET 2012 Q230 Errorless 1. Work Done by Constant Force MCQ
A force acts on a 30 g particle in such a way that the position of the particle as a function of time is given by $x = 3t - 4t^{2} + t^{3}$ , where x is in metres and t is in seconds. The work done during the first 4 seconds is
A.
5.28 J
B.
450 mJ
C.
490 mJ
D.
530 mJ
MP PMT/PET 1998; Pb. PMT 2002 Q231 Errorless 2. Work Done by Variable Force MCQ
Two springs of spring constants 1500 N/m and 3000 N/m respectively are stretched with the same force. They will have potential energy in the ratio
A.
4:1
B.
1:4
C.
2:1
D.
1:2
BHU 1998; EAMCET 2001; CBSE PMT 2006; WB-JEE 2008 Q232 Errorless 2. Work Done by Variable Force MCQ
A body of mass 3 kg is under a force, which causes a displacement in it given by $S = \frac{t^{3}}{3}$ (in m). Find the work done by the force in first 2 seconds
A.
2 J
B.
3.8 J
C.
5.2 J
D.
24 J
AIIMS 1998; UPSEAT 2000; JIPMER 2001; Kerala PMT 2004 Q233 Errorless 3. Conservation of Energy and Momentum MCQ
A light and a heavy body have equal momenta. Which one has greater K.E
A.
The light body
B.
The heavy body
C.
The K.E. are equal
D.
Data is incomplete
AIIMS 1998, 2002; KCET 2000; CPMT 2003; J & K CET 2004; Kerala PMT 2005; RPMT 2006 Q234 Errorless 3. Conservation of Energy and Momentum MCQ
If the K.E. of a particle is doubled, then its momentum will
A.
Remain unchanged
B.
Be doubled
C.
Be quadrupled
D.
Increase $\sqrt{2}$ times
AFMC 1998; RPMT 1999; DPMT 2000; MP PET 2004 Q235 Errorless 3. Conservation of Energy and Momentum MCQ
The kinetic energy of a body of mass 3 kg and momentum 2 Ns is
A.
1 J
B.
$\frac{2}{3}J$
C.
$\frac{3}{2}J$
D.
4 J
BHU 1998, 2005; JIPMER 2001, 02; AFMC 2005 Q236 Errorless 6. Perfectly Inelastic Collision MCQ
Which of the following is not a perfectly inelastic collision
A.
Striking of two glass balls
B.
A bullet striking a bag of sand
C.
An electron captured by a proton
D.
A man jumping onto a moving cart
JIPMER 1997; CBSE PMT 1999; BHU 2000; RPMT 2000; Odisha JEE 2002 Q237 Errorless 1. Work Done by Constant Force MCQ
A body moves a distance of 10 m along a straight line under the action of a force of 5 N. If the work done is 25 joules, the angle which the force makes with the direction of motion of the body is
A.
0°
B.
30°
C.
60°
D.
90°
MP PMT 1997, 2000; JIPMER 2000; AIEEE 2002, 04; DCE 2006 Q238 Errorless 2. Work Done by Variable Force MCQ
A uniform chain of length 2m is kept on a table such that a length of 60cm hangs freely from the edge of the table. The total mass of the chain is 4kg. What is the work done in pulling the entire chain on the table
A.
7.2 J
B.
3.6 J
C.
120 J
D.
1200 J
MP PMT 1997; CPMT 1997; DPMT 2001 Q239 Errorless 3. Conservation of Energy and Momentum MCQ
If a lighter body (mass $M_{1}$ and velocity $V_{1}$ ) and a heavier body (mass $M_{2}$ and velocity $V_{2}$ ) have the same kinetic energy, then
A.
$M_{2}V_{2} < M_{1}V_{1}$
B.
$M_{2}V_{2} = M_{1}V_{1}$
C.
$M_{2}V_{1} = M_{1}V_{2}$
D.
$M_{2}V_{2} > M_{1}V_{1}$
BHU 1997; MP PET 2000; CBSE PMT 2000; MH CET 2000; JIPMER 2001, 02; AMU (Med.) 2002; DPMT 2003 Q240 Errorless 4. Power MCQ
The power of a pump, which can pump 200kg of water to a height of 200m in 10sec is $(g=10m/s^{2})$
A.
40 kW
B.
80 kW
C.
400 kW
D.
960 kW
MP PMT 1997; CBSE PMT 1998; AIIMS 2000; UPSEAT 2001; MP PET 2001, 02, 07; Kerala PMT 2008 Q241 Errorless 5. Elastic and Inelastic Collision MCQ
Two equal masses $m_{1}$ and $m_{2}$ moving along the same straight line with velocities +3 m/s and -5 m/s respectively collide elastically. Their velocities after the collision will be respectively
A.
+4 m/s for both
B.
-3 m/s and +5 m/s
C.
-4 m/s and +4 m/s
D.
-5 m/s and +3 m/s
CPMT 1997; MP PET 1999; DPMT 1999, 2005; JIPMER 2000 Q242 Errorless 6. Perfectly Inelastic Collision MCQ
A particle of mass m moving eastward with a speed v collides with another particle of the same mass moving northward with the same speed v. The two particles coalesce on collision. The new particle of mass 2m will move in the north-easterly direction with a velocity
A.
v/2
B.
2v
C.
v/ $\sqrt{2}$
D.
v
CBSE PMT 1997; AIIMS 2001; Pb. PMT 2001; J & K CET 2005; AIEEE 2008 Q243 Errorless 6. Perfectly Inelastic Collision MCQ
A body of mass 4 kg moving with velocity 12 m/s collides with another body of mass 6 kg at rest. If two bodies stick together after collision, then the loss of kinetic energy of system is
A.
Zero
B.
288 J
C.
172.8 J
D.
144 J
BHU 1997; J & K CET 2010; CBSE PMT (Pre.) 2011 Q244 Errorless 8. Graphical Questions MCQ
Force F on a particle moving in a straight line varies with distance d as shown in the figure. The work done on the particle during its displacement of 12 m
A.
13 J
B.
18 J
C.
21 J
D.
26 J
CBSE PMT 1996; MP PMT/PET 1998; AIIMS 1999; JIPMER 2001, 02; RPMT 2005 Q245 Errorless 6. Perfectly Inelastic Collision MCQ
A particle of mass m moving with velocity v strikes a stationary particle of mass 2m and sticks to it. The speed of the system will be
A.
v/2
B.
2v
C.
v/3
D.
3v
Haryana CEE 1996; BVP 2003 Q246 Errorless 6. Perfectly Inelastic Collision MCQ
Two putty balls of equal mass moving with equal velocity in mutually perpendicular directions, stick together after collision. If the balls were initially moving with a velocity of $45\sqrt{2} ms^{-1}$ each, the velocity of their combined mass after collision is
A.
$45\sqrt{2} ms^{-1}$
B.
$45ms^{-1}$
C.
$90ms^{-1}$
D.
$22.5\sqrt{2} ms^{-1}$
AFMC 1996, 2006; BHU 2001; DCE 2004, 09; AIIMS 2006; UP CPMT 2006 Q247 Errorless 6. Perfectly Inelastic Collision MCQ
In an inelastic collision, what is conserved
A.
Kinetic energy
B.
Momentum
C.
Both a) and b)
D.
Neither a) nor b)
EAMCET (Engg.) 1995; WB-JEE 2009 Q248 Errorless 3. Conservation of Energy and Momentum MCQ
Two bodies of masses 2m and m have their K.E. in the ratio 8:1, then their ratio of momenta is
A.
1:1
B.
2:1
C.
4:1
D.
8:1
Manipal MEE 1995; AIEEE 2002, 06; Pb. PET 2004; CBSE PMT 2005; KCET 2007; Odisha JEE 2008 Q249 Errorless 3. Conservation of Energy and Momentum MCQ
A bomb of mass 9kg explodes into 2 pieces of mass 3kg and 6kg. The velocity of mass 3kg is 1.6 m/s, the K.E. of mass 6kg is
A.
3.84 J
B.
9.6 J
C.
1.92 J
D.
2.92 J
CBSE PMT 1995; AIEEE 2003 Q250 Errorless 5. Elastic and Inelastic Collision MCQ
A $^{238}U$ nucleus decays by emitting an alpha particle of speed $v \, ms^{-1}$ . The recoil speed of the residual nucleus is (in $ms^{-1}$ )
A.
-4v / 234
B.
v / 4
C.
-4v / 238
D.
4v / 238